The failure rates of overhead distribution system components

Abstract

A study of 85 rural and 95 urban overhead distribution feeders from the Pacific Gas and Electric system was made to develop generic service time failure rates for seven OH component types: Transformers Switches FUSeS CapacitorsReclosers Voltage Regulators Conductor for both rural and urban installations.These failure rates are in reality "best estimates" of the actual failure rates of the components. A range of deviations about these "best estimates" can be assessed at various confidence levels. Only transformers were found to exhibit a significant difference in failure rate between rural and urban installations.The component failures contributed about 15% of the total number of sustained outages for the OH feeders of this study. The remaining 85% of the sustained outages were due to external factors (75%) and loss of supply (10%). This suggests that overhead distribution system reliability is relatively insensitive to component failures, at the existing component failure rate levels.

Hybrid methodology to analyse reliability and techno‐economic evaluation of microgrid configurations

“…In the evaluation of overall microgrid reliability protection equipment apart from relay (i.e. PMU) are considered with all-time availability, as their failure rate is quite negligible [34]. Communication infrastructure is used to provide the RER power generation information through the relay to the control centre and also the control commands from the control centre to protection devices.…”

Analyzing Mission Impact of Military Installations Microgrid for Resilience

“…Failure rates of the components in the microgrid come from publicly available data sources [66][67][68][69][70]. Reliability block diagrams were developed to calculate the overall failure rate for each power line link within the microgrid, including between the PV array, the ESS, the diesel generators, the loads, and other microgrid components.…”

“…Table 3 shows the input values for probability of failure (used in later EEDMI calculations) and MTTR, and the output of the mean and standard deviation of M s for each failure mode. The failure data come from publicly available data sources [66][67][68][69][70]. The results shown in Table 3 indicate that in the baseline microgrid architecture the PV array is not needed to reduce M s , which is expected because the PV is sized as a demonstration renewable energy project that is under-sized to support situations where one of the two diesel generators fail.…”

A new approach for reliability-centered maintenance programs in electric power distribution systems based on a multiobjective genetic algorithm

“…These values correspond to 15% of the limit set up by the regulatory agencies in Brazil. These percentages were adopted based on the results of studies regarding component failures on overhead distribution systems [26]. The maximum supported value adopted for the failure probability (unreliability) ur max of capacitor banks in equation 11is 0.30 for all e cb ∈ E CB .…”